The signs, written in English, were apologizing for the "mess" in the capital caused by the "forced begging" problem.
Stockholm has recently been faced with a tremendous surge in EU migrants, mostly from Romania and Bulgaria. A recent study indicated that the number of migrants has almost doubled since last year reaching 4,000 people.
"It is written in English and explains the situation to tourists. Many get surprised and concerned when they come here, especially if they visited Sweden maybe 20 years ago and have come back again," Sweden Democrat spokesperson Henrik Vinge told The Local Sweden.
Fixade SDs annons — vem hos SL ska ha mitt nya original? pic.twitter.com/pKkyisVrM0
— Bravefart (@pinsamtystnad) 3 августа 2015
"Sorry about the mess here in Sweden. We have a serious problem with forced begging!" the signs read.
Sweden Democrats are targeting tourists inconvenienced by poor Roma people with the "organized begging" lie. pic.twitter.com/K797I7I9tU
— aslı (@Julia_ATC) 3 августа 2015
The controversial adverts have triggered fierce public criticism. Stockholm's transport company has received hundreds of complaints, while Swedish protesters launched a campaign against the "racist" posters. About 13,000 Facebook users have signed up to attend the protest against the advertising campaign.
"We were shocked that our subway company allows these types of racist opinions about a group of people in society. They call them [the beggars] a mess like they are going to clean them away," Swedish radio host Amie Bramme Sey stressed.
By Tuesday afternoon the Swedish Chancellor of Justice had received almost 56 reports lambasting the Democrats' controversial initiative and launched an investigation into the case aimed to find out whether the anti-begging campaign constitutes hate speech.